Power unit



April 9, 1946. F. P. GERHARDT POWER UNIT Filed Dec. 12, 1940 3 Sheets-Sheet l III/l/ INVEINTOR fled P Gerhard? BY April 9, 1946. F. P. GERHARDT 2,398,221

POWER UNIT Filed Dec. 12, 1940 3 Sheets-Sheet 2 INVENTOR. fled P G'cr/bard' BY %m April 9, 1946. F. P. GERHARDT 2,398,221

POWER UNIT 5 Sheets-Sheet 5 Filed Dec. 12, 1940 fled P Gerhardwig;

Patented Apr. 9, 1946 POWER UNIT Fred P. Gerhardt, Milwaukee, Wis., assignor, by direct and mesne assignments, of thirty-nine per cent to Bertha Gerhardt and per cent to Earl A. Everett, both of Los Angeles County,

Calif.

Application December 12, 1940, Serial No. 369,759

2 Claims. (01. 123-46) 4 diameter than the power cylinder I2, from which This invention relates to prime movers or power units and the general object of the invention is to provide a power unit driven by internal combustion which will have a greatly increased eificiency as compared with the most efficient internal combustion engines known today. I also aim to conserve a large proportion of the heat (B. t. u.s) ordinarily lost by radiation or in the cooling system or in the exhaust, and to convert this heat into power. The invention further provides a power unit of enhanced efficiency-which may burn gasoline, kerosene, fuel oil or powdered coal and which may be used as a marine engine,

an automotive power plant or an airplane engine, and indeed, wherever an internal combustion engine finds a, field of usefulness. Other objects will appear from the following description of several embodiments of the invention.

In the accompanying diagrammatic drawings: Fig. 1 is a longitudinal sectional view of a simple type of engine;

Fig. 2 is a longitudinal section on line 2-2 of Fig. 1;

Fig. 3 is a cross section on line 3--3 of Fig. 2;

Fig. 4 is a longitudinal section showing another form of engine employing two stage air compression;

Fig. 5 is an elevation showing still another form of engine much like the engine of Figs. 1 and 2 but assembled with an exhaust-driven turbine and being equipped with a starter.

Referring particularly to the drawings, and first to Figs. 1, 2 and 3, an internal combustion engine is there shown comprising a piston it fast to a piston rod ii and adapted to reciprocate in a truncated cylinder i 2 responsive to explosions alternately at opposite ends of the cylinder. While these explosions may take place because of a spark ignitingan explosive charge delivered by a carburetor, as in any automobile engine, I prefer to use a liquid fuel injector l3 at either end of cylinder l2, said injector being of a type known in the art of Diesel engines. The mechanism by which a measured amount of fuel is delivered at the proper instant to each injector I3 is not shown becauseit may be one of several types and it forms no part of the present invention. At one end of piston rod ii is a compressor piston It reciprocable in an air compressor cylinder l5, and at the other end of the piston rod is another compressor piston l6 reciprocable in a compression cylinder l7, compression cylinders I6, I! being axially alined with power cylinder l2. Both compression cylinders l5, I! are of the same size and both are shown as being larger in they are sealed ofl by the cylinder heads l8, I9 respectively; but the compression cylinders may each be smaller than the power cylinder.

When the parts are in the position of Figs. 1 and 2, piston III has compressed a charge of air in the left end of cylinder [2, and the injector l3 at that end will inject fuel, causing an explosion to take place spontaneously in the left end of the cylinder. As viewed in Fig. 1, compressor piston 14 has fully compressed air previously admitted from the atmosphere into cylinder I 5, and the compressed air is escaping past exhaust valve 20 into a pipe 2| which leads to the right end of cylinder I2. At the same instant, a fresh charge of air enters cylinder l5 past inlet valve 22. Pipe M has a check valve 23 near its discharge end, where it'is connected with a semi-circular intake manifold 24 on the outside of cylinder l2, see Fig. 3. There are two pairs of nozzles 25 at opposite ends' of the power cylinder, the nozzles of each pair being at preferably diametrically opposite points on the power cylinder, discharging the highly compressed air into the adjacent end of said cylinder. Nozzles 25 considerably increase the velocity of the compressed air. This compressed air of course scavenges the right end of the power cylinder, the hot gases, with some of the scavenging air, being exhausted through a port 26 in the side of the cylinder, said port 26 leading to a branch 21 of an exhaust manifold 28 which may lead to a turbine 29, as in the arrangement of Fig. 5, or to some other type of engine or prime mover. Said compressed air, whirling at great speed within the right end of the cylinder, because of the disposition of the nozzles 25, though hot from the compression has a considerably lower temperature than the cylinder and cylinder head it and hence soaks up excess heat from the same, this being the second function of the compressed air charge. The part of the compressed air which remains in the cylinder l2 (right hand end) forms a fresh explosive charge when fuel is later injected in said end from injector l3. This is the third function performed by the compressed air.

'Now assuming that the explosion has taken place in the left end of the cylinder, piston m is moved to the right and when it passes outlet or port 26a (corresponding to port 26) it starts to compress further the compressed air charge in the right end of the cylinder. Check valve 23 immediately closes, as does check valve 30 in inlet 3| leading from compression cylinder Il. Compression piston IS in cylinder ll starts moving to the right, causing inlet valve 32 to close and inlet valve 33 to open. Air in front of the moving face of piston I6 is of course compressed, there being, for the moment, no outlet for the same. But when piston ill exposes the port 28a, which acts like a valve, valve 34, which had previously been held closed by its spring, opens to discharge compressed air through pipe 35, past check valve 36, through intake manifold 31, through nozzles 25 into the left end of cylinder l2. Thus the opening of port 26a leading to the discharge manifold 28 effects opening of valve 34, allowing a fresh charge of compressed air to enter the left end of cylinder i2 to perform the three functions already mentioned in describing the action at the right end of the cylinder l2. Opening of port 26 likewise controls opening of valve 20 controlling discharge of compressed air from compression cylinder [5.

Again assuming that the charge in the left end of cylinder l2 has just been fired, as piston lmoves to the right to cause compressor piston ii to compress air in cylinder IT, as just described,.

compressor piston ll simultaneously starts moving to the right to compress air in the right end of compression cylinder i5. Compression in'cylinder l takes place because inlet valve 22 immediately closes, and valve 39 (in inlet pipe 40, connected with intake manifold 31) remains closed because of its spring. However, when piston l0 exposes port 280 in its movement to the right. valve 39 opens, permitting the air compressed by piston I4 to be discharged through inlet pipe 40 to the left end of power cylinder [2, and said charge of compressed air mingles with the charge of compressed air from pipe 35, the two charges whirling around inside the left end of cylinder i2 and scavenging and cooling the same and preparing it for the next explosion. Valve 30 corresponds to valve 39, permitting compressed air from cylinder II to pass through pipe 31 into the right end of power cylinder I2 at the same time compressed air from the left end of cylinder l5 passes through pipe 2| into the same end of the power cylinder.

From the foregoing, it will be clear that each compressor piston ll, l6 compresses air in each stroke. Compressed air from both cylinders l5, I1 is delivered at the same time to either end of power cylinder i2; and the combined charge of compressed air, after scavenging and cooling as described above, remains in suflicient volume and under sufllcient pressure to insure high pressures in power cylinder l2 such as will spontaneously ignite the fuel charge, as in any Diesel engine.

aapaam whirling motion of the charges of compressed air for the scavenging and cooling mentioned above. Also these doughnut-shaped clearance spaces insure a sufllcient volume of highly compressed air and gases of combustion to effect the delivery of power-generating gases through the exhaust manifold 28. It is one of the aims of the invention not to use up the heat and power of the fuel and compressed air in the described engine, but to deliver heat and power through the exhaust manifold to any engine or turbine. Indeed, the described power unit is not primarily an engine, but rather a generator, since it generates vast quantities of heated gases which are themselves conducted to a true engine or motor to accomplish useful work. A turbine 42, as in Fig. 5, if direct-connected to a generator like that of Fig. 1, will be driven at high speed by the gases delivered from said generator, and will have a long life because its blades cannot be injured by highly heated gases, since the gases in the generator by doing useful work have had much of their heat abstracted; and furthermore the compressed air dilutes and moderates the gases of combustion and hence prevents any damage to the turbine blades.

Another highly valuable feature of the generator of Figs. 1 and 2 is the fact that the compressed air charges strike the power piston and the interior of the combustion chamber once during each cycle. This direct contact of cooling gases with the interior of the power cylinder assures cooling of the hottest parts of the cylinder l2 and piston Ill without depending on radiation through the walls of the power cylinder. Thus no external cooling system need be used, and the unit may be operated at exceedingly high speeds. Furthermore, since an external cooling system is not needed, and the power piston and cylinder are cooled uniformly thus avoiding internal stresses in the metal, the power unit may be built much larger than is feasible with engines having external cooling systems.

It will be observed that piston Iii is a freefloating piston, that is, there is no crank and crankshaft, or other mechanical means to limit its stroke in either direction; hence its speed is not limited by mechanical connections and shaft load conditions. As piston l0 approaches either end of cylinder I2, a cushion of compressed air tends to check it, and this checking or elastic cushioning is supplemented by the cushions of It will likewise be clear that the compressed air charge is further compressed by the power piston I0, generating heat which is dissipated partly by radiation from the walls of cylinder l2 but which is largely absorbed by the scavenging blast of the subsequent compressed air charge.

It will be particularly noted that the piston l0 has a cavity H on each end, said cavity being annular, and cylinder heads l8, l9, likewise have annular cavities I803, i9a respectively. Cavity "a is complemental to cavity ll on that side of the piston and cavity l9a is complemental to cavity ll -on the corresponding piston end. Thus Fig. 1'). This clearance space, forming altercompressed air in cylinders l5 and I1. Furthermore, the fuel charge is injected before the piston can strike the end of cylinder l2, causing an explosion which reverses the movement of the piston. Thus no springs or checks or other mechanical connections for safety or control are necessary, in the simple form of the invention now under consideration.

It will be clear from the drawings that the described power unit is perfectly balanced and that it will operate at high speed free of vibration,

when two units are set in line and synchronized in revolutions so that the thrust from one counteracts the thrust of the other. Unlike a Diesel engine which requires a heavy base due to the there is an unusually large clearance space at a nately at opposite ends of the firing or powergenerating cylinder, may be said to be doughnutshaped, and is of great importance to insure a severe thrust on the crankshaft bearings, the weight of my power unit may be low, and its cost may be low because the parts are few.

Another important feature of the invention (which will be apparent after studying Fig. 1)

is the fact that when one port 28, 26a is closed by piston III, the other port 28a, 26 is open or partly open, thus insuring a constant pressure and absolutely continuous flow of hot gases from the generator to the turbine, thereby eliminating losses due to changing pressure ratios.

Now referring to Fig. 4, a piston 50 is there sh'own an a piston rod extending centrally of a power cylinder 52. Except for an increased length of piston rod 5|, the parts 50, 5| and 52 are exactly like the piston, piston rod and power cylinder of Figs. 1 and 2. Power cylinder 52 has cylinder heads 59, 54 at opposite ends, and the piston rod 5| extends through both cylinder heads, which form bearings for the reciprocating piston rod. Axially alined with power cylinder 52 at one end are two compression cylinders 55,

5, cylinder 58 being the larger, and being at the extreme end of the power unit. A compressor piston 51 is rigidly secured to piston rod 5| to operate in compression cylinder 55, and a compression piston 58 operates in cylinder 58. At the other end of the power unit a compression cylinder 59 is secured, and a compressor piston 80, fast to piston rod 5|, works in cylinder 59. Axially alined with cylinder 59 is a larger compression cylinder iii in which a piston 62, fast to piston rod. 5|, reciprocates. The two large compression cylinders 56, 8| at the opposite ends of the power unitare each provided with inlet valves 88, 54, 85, 59 which on each stroke of the pistons 58, 82 open to admit atmospheric air to one side of said pistons and close to prevent escape of compressed air. The action of valves 53, 58, 95, 58 is exactly like the action of the inlet valves 32, 38, 22, 98 of Fig. 1. Each stroke of piston rod 5| causes air to be compressed by pistons 58, 52 in the respective cylinders 58, 8|, and this compressed air is conducted away as will now be described.

The relatively large volume of compressed air from cylinder 59 is forced past a check valve 67, when the stroke is from left to right as the parts are viewed in Fig. 4, said check valve being of course closed by a. spring, not shown, the action being the same as that of spring pressed valve 8 5, Fig. 1. Valve 87 controls movement of compressed air through a pipe 68, and said pipe leads to compression cylinder 55. A check valve 89 is at the discharge end of pipe co and it opens when valve or opens, to permit flow of compressed air from cylinder 56 (the low stage cylinder) to cylinder 55 (the high stage cylinder). Compressed air from pipe t8 obviously provides a charge for piston all which is compressed further when piston 5? moves from right to left, which will be on its next stroke. Thus air compressed by piston 58 on its left to right stroke is admitted to the left side of piston 57 to be further compressed. Air compressed by piston 58 on its right to left stroke lifts a spring pressed check valve is controlling a port ii between cylinders 55 and 5b, and passes directly into cylinder $5 to be compressed further during the left to right stroke of piston 57.

Exactly the same construction is at the other end of the power unit. A spring pressed check valve 13 admits compressed air discharged from compression cylinder 8| to a pipe or conduit 14 leading to compression cylinder 59, and a spring pressed check valve '55 is at one end of cylinder E9 to admit said compressed air when check valve 78 lifts. A port 16 between cylinders 59 and 8| has a spring pressed check valve H and permits compressed air from cylinder 8| to flow directly into cylinder 59, when pistons 89, 82, are moving to the right. Thus the left stroke ofpiston 82 causes compressed air to enter the right end of cylinder 59, and the right stroke of. piston 82 causes compressed air to enter the left end of cylinder 59. In either case, the compressed airdischarged from cylinder 8| is further compressed by piston 88. 4

Air under high pressure from cylinders 55, 59 is conducted to the opposite. ends of power cylinder 52 during each stroke of piston 50, thereby to scavenge the power cylinder, to cool it and to admit a charge of compressed air which will form an explosive mixture when the fuel is injected (as already described in connection with Figs. 1 and 2). At each end of the power cylinder a semiannular intake manifold l8, I9 is arranged, with venturis 88 preferably at diametrically opposite points, the venturis 89 being preferably like venturis 25. The intake'manifolds 19, 19 may extend to the inner or adjacent ends of the high compression cylinders 55, 59 respectively and check valves 8|, 82 may control flow of highly compressed air from cylinders 55, 59 into said intake manifolds. With the parts in the positions shown in Fig. 4, highly compressed air is discharged from cylinder past the venturi 80 into power cylinder 52; and said air scavenges the power cylinder, absorbs much of its heat, and mixed with the products of combustion part of said air passes out through port 83 leading to branch 84a of the exhaust manifold 85. .A similar port 83a is on the other side of the power cylinder and it is connected with branch 84b of manifold 85. Exhaust manifold 85 is also an intake or pressure pipe leading to a turbine (as in Fig. 5) or to an expansion engine (not shown) or to' a system of expansion nozzles (not shown) providing jet propulsion.

At the same instant that highly compressed air is discharged into the right end of the power cylinder from high compression cylinder 55, an equal charge of compressed air under like high pressure is discharged into the same end of the power cylinder from high compression cylinder 59. A check valve 85 is located at the left end of cylinder 59 and is lifted off its seat 81 by the excessively high pressure of air compressed by the right to left stroke of piston 68, but is otherwise held on its seat by spring 88'. Compressed air forced past valve 88 flows through a pipe or conduit 89 the discharge end of which terminates in intake manifold 18, and a check valve 99 is at said discharge end. Thus the right to left strokes of the high pressure pistons 51, 68

cause a double charge of highly compressed air to flow into intake manifold 78, thence to the power cylinder. Another pipe 9| discharges highly compressed air from cylinder 55 past check valve 92 to intake manifold 79 and thence to the left side of the power cylinder; and a check valve 93, held on seat 9% by its spring, controls flow through pipe 9|. 7

The form of Fig. 4, it will now be clear, is substantially the same as that of Fig. 1 except for the employment of two two-stage air compressors in lieu of two one-stage. compressors. A great many additional changes and modifications may be made, within the scope of the invention. Therefore the present invention is not to be considered as limited to the forms described and shown, but is defined by the appended claims.

Having described the invention, what I claim as new and desire to secure by Letters Patent is:

l. A power unit comprising, in combination, a power cylinder; a piston and piston rod reciprocable in'the power cylinder; means feeding fuel to the opposite ends of the cylinder; a pair of compressor pistons secured to the opposite ends of said piston rod; the diameter of said compressor pistons being larger than the diameter of the power piston; compression cylinders in which said compressor pistons reciprocate; conduits or pipes leading from each end of each compression cylinder to both ends of the power cylinder; inlet valves for each end of each compression cylinder; check valves to control flow of air through said conduits or pipes; an exhaust manifold having two branches; and ports formed in the wall of the power cylinder and discharging into the branches of the exhaust manifold; the ports being so constructed and arranged that said ports are always partly uncovered by the piston in the power cylinder or else one of the ports is completely uncovered.

2. The invention according to claim 1 wherein there are two pairs of compressor pistons secured to the piston rod, two of the compressor pistons being at the opposite endsof the piston- FRED P. GERHARDT.. 

